import os
import secrets
from flask import Flask


def create_app(test_config=None):
    """
    应用工厂：创建应用 并且返回
    :param test_config:
    :return:
    """
    # create and configure the app
    # instance_relative_config=True 声明配置文件 和flaskr包 同级
    app = Flask(__name__, instance_relative_config=True)
    app.config.from_mapping(
        SECRET_KEY=secrets.token_hex(),
        DATABASE=os.path.join(app.instance_path, 'flaskr.sqlite'),
    )

    if test_config is None:
        # load the instance config, if it exists, when not testing
        app.config.from_pyfile('config.py', silent=True)
    else:
        # load the test config if passed in
        app.config.from_mapping(test_config)

    # ensure the instance folder exists
    try:
        os.makedirs(app.instance_path)
    except OSError:
        pass

    # a simple page that says hello
    # @app.route('/')
    # def index():
    #     return '<h1>欢迎来到首页</h1>'

    from . import db
    db.init_app(app)

    from . import auth
    app.register_blueprint(auth.bp)

    from . import blog
    app.register_blueprint(blog.bp)
    # app.add_url_rule('/', endpoint='index')

    from . import bigdata
    app.register_blueprint(bigdata.bp)

    return app

# 运行指令： flask --app flaskr run --debug
